The Convair B-36 "Peacemaker"[N 1] is a strategic bomber built by Convair and operated by the United States Air Force (USAF) from 1949 to 1959. The B-36 is the largest mass-produced piston-engined aircraft ever built, it had the longest wingspan of any combat aircraft ever built, at 230 ft (70.1 m). The B-36 was the first bomber capable of delivering any of the nuclear weapons in the U.S. arsenal from inside its four bomb bays without aircraft modifications. With a range of 10,000 mi (16,000 km) and a maximum payload of 87,200 lb (39,600 kg), the B-36 was capable of intercontinental flight without refuelling.

The United States would need a new class of bomber which would reach Europe and return to bases in North America,[4] necessitating a combat range of at least 5,700 miles (9,200 km), the length of a Gander, Newfoundland–Berlin round trip. The USAAC therefore sought a bomber of truly intercontinental range,[5][6] similar to the German Reichsluftfahrtministerium's (RLM) ultra-long-range Amerikabomber program, the subject of a 33-page proposal submitted to ReichsmarschallHermann Goering on May 12, 1942.

The USAAC sent out the initial request on 11 April 1941, asking for a 450 mph (720 km/h) top speed, a 275 mph (443 km/h) cruising speed, a service ceiling of 45,000 ft (14,000 m), beyond the range of ground-based anti-aircraft fire, and a maximum range of 12,000 miles (19,000 km) at 25,000 ft (7,600 m).[7] These requirements proved too demanding for any short-term design—far exceeding the technology of the day—[5] so on 19 August 1941 they were reduced to a maximum range of 10,000 mi (16,000 km), an effective combat radius of 4,000 mi (6,400 km) with a 10,000 lb (4,500 kg) bombload, a cruising speed between 240 and 300 mph (390 and 480 km/h), and a service ceiling of 40,000 ft (12,000 m),[4] above the maximum effective altitude of all of Nazi Germany's anti-aircraft Flak guns, save for the rarely deployed 12.8 cm FlaK 40 heavy Flak cannon.

As the Pacific war progressed, the air force increasingly needed a bomber capable of reaching Japan from its bases in Hawaii, and the development of the B-36 resumed in earnest. Secretary of War Henry L. Stimson, in discussions with high-ranking officers of the USAAF, decided to waive normal army procurement procedures, and on 23 July 1943 – some fifteen months after the Germans' Amerikabomber proposal's submission made it to their RLM authority; and ironically, the same day that, in Germany, the RLM had ordered the Heinkel firm to design a six-engined version of their own, BMW 801E-powered Amerikabomber design proposal[8] – the USAAF submitted a "letter of intent" to Convair, ordering an initial production run of 100 B-36s before the completion and testing of the two prototypes.[9] The first delivery was due in August 1945, and the last in October 1946, but Consolidated (by this time renamed Convair after its 1943 merger with Vultee Aircraft) delayed delivery, the aircraft was unveiled on 20 August 1945 (three months after V-E Day), and flew for the first time on 8 August 1946.[10]

After the establishment of an independent United States Air Force in 1947, the beginning in earnest of the Cold War with the 1948 Berlin Airlift, and the 1949 atmospheric test of the first Soviet atomic bomb, American military planners sought bombers capable of delivering the very large and heavy first-generation atomic bombs.

The B-36 was the only American aircraft with the range and payload to carry such bombs from airfields on American soil to targets in the USSR, the modification to allow the use of larger atomic weapons on the B-36 was called the "Grand Slam Installation".[11]

The B-36 was arguably obsolete from the outset, being piston-powered, coupled with the widespread introduction of first generation jet fighters in potential enemy air forces,[3][12] but its jet rival, the Boeing B-47 Stratojet, which did not become fully operational until 1953, lacked the range to attack the Soviet homeland from North America without aerial refueling and could not carry the huge first-generation Mark 16 hydrogen bomb.

The other American piston bombers of the day, the B-29 and B-50, were also too limited in range to be part of America's developing nuclear arsenal.[13]Intercontinental ballistic missiles (ICBMs) did not become sufficiently reliable until the early 1960s. Until the Boeing B-52 Stratofortress became operational in 1955, the B-36, as the only truly intercontinental bomber, continued to be the primary nuclear weapons delivery vehicle of the Strategic Air Command (SAC).[3]

Convair touted the B-36 as the "aluminum overcast", a so-called "long rifle" giving SAC truly global reach,[3] during General Curtis LeMay's tenure as head of SAC (1949–57), the B-36, through intense crew training and development, formed the heart of the Strategic Air Command. Its maximum payload was more than four times that of the B-29, and exceeded that of the B-52.

The B-36 was slow and could not refuel in midair, but could fly missions to targets 3,400 miles (5,500 km) away and stay aloft as long as 40 hours.[3] Moreover, the B-36 was believed to have "an ace up its sleeve": a phenomenal cruising altitude for a piston-driven aircraft, made possible by its huge wing area and six 28-cylinder engines, putting it out of range of most of the interceptors of the day, as well as ground-based anti aircraft guns.[3]

The huge new XB-36 alongside the first superbomber, the Boeing B-29 Superfortress. The wings of the 'Peacemaker' were 7 feet (2.1 m) thick at the root.

The XB-36 showing the giant single tires. Production aircraft had a four-wheel main gear instead.

Closeup of the XB-36's single-wheeled portside main gear unit

Consolidated Vultee Aircraft Corporation (later Convair) and Boeing Aircraft Company took part in the competition, with Consolidated winning a tender on 16 October 1941. Consolidated asked for a $15 million contract with $800,000 for research and development, mockup, and tooling. Two experimental bombers were proposed, the first to be delivered in 30 months, and the second within another six months. Originally designated Model B-35, the name was changed to B-36 to avoid confusion with the Northrop YB-35 piston-engined flying wing bomber,[5][14] against which the B-36 was meant to compete for a production contract.

Throughout its development, the B-36 encountered delays. When the United States entered World War II, Consolidated was ordered to slow B-36 development and greatly increase Consolidated B-24 Liberator production, the first mockup was inspected on 20 July 1942, following six months of refinements. A month after the inspection, the project was moved from San Diego, California, to Fort Worth, Texas, which set back development several months. Consolidated changed the tail from a twin-tail to a single, thereby saving 3,850 pounds (1,750 kg), but this change delayed delivery by 120 days.

As a result, the Air Force mandated that Consolidated design a four-wheeled bogie-type wheel system for each main gear unit instead, which distributed the pressure more evenly and reduced weight by 1,500 pounds (680 kg).[5][16][17] Changes in the United States Army Air Forces (USAAF) requirements did add back any weight saved in redesigns, and cost more time. A new antenna system needed to be designed to accommodate an ordered radio and radar system, the Pratt & Whitney engines were redesigned, adding another 1,000 pounds (450 kg).[18]

A B-36 airframe undergoing structural stability tests. Note for scale the three men in the balcony at the extreme right of the photograph.

The B-36 took shape as an aircraft of immense proportions, it was two-thirds longer than the previous "superbomber", the B-29. The wingspan and tail height of the B-36 exceeded those of the 1960s Soviet Union's Antonov An-22Antheus military transport, the largest ever propeller-driven aircraft put into production.[3] Only with the advent of the Boeing 747 and the Lockheed C-5 Galaxy, both designed two decades later, did American aircraft capable of lifting a heavier payload become commonplace.

The wings of the B-36 were large even when compared with present-day aircraft, exceeding, for example, those of the C-5 Galaxy, and enabled the B-36 to carry enough fuel to fly the intended long missions without refueling, the maximum thickness of the wing, measured perpendicular to the chord, was 7.5 feet (2.3 m) thick, containing a crawlspace that allowed access to the engines.[19] The wing area permitted cruising altitudes well above the operating ceiling of any 1940s-era operational piston and jet-turbine fighters. Most versions of the B-36 could cruise at over 40,000 feet (12,000 m).[20] B-36 mission logs commonly recorded mock attacks against U.S. cities while flying at 49,000 feet (15,000 m).[citation needed] In 1954, the turrets and other nonessential equipment were removed (not entirely unlike the earlier Silverplate program for the atomic bomb-carrying "specialist" B-29s) that resulted in a "featherweight" configuration believed to have resulted in a top speed of 423 miles per hour (681 km/h),[21] and cruise at 50,000 feet (15,000 m) and dash at over 55,000 feet (17,000 m), perhaps even higher.[22]

The large wing area and the option of starting the four jet engines supplementing the piston engines in later versions gave the B-36 a wide margin between stall speed (VS) and maximum speed (Vmax) at these altitudes. This made the B-36 more maneuverable at high altitude than the USAF jet interceptors of the day, which either could not fly above 40,000 ft (12,000 m), or if they did, were likely to stall out when trying to maneuver or fire their guns.[23] However, the U.S. Navy argued that their McDonnell F2H Banshee fighter could intercept the B-36, thanks to its ability to operate at more than 50,000 feet (15,000 m).[24] The USAF declined the invitation from the U.S. Navy for a fly-off between the Banshee and the B-36. Later, the new Secretary of Defense, Louis A. Johnson, who considered the U.S. Navy and naval aviation essentially obsolete in favor of the U.S. Air Force and Strategic Air Command, forbade putting the Navy's claim to the test.[25]

The propulsion system of the B-36 was unique, with six 28-cylinder Pratt & Whitney R-4360 'Wasp Major' radial engines mounted in an unusual pusher configuration, rather than the conventional four-engine, tractor propeller layout of other heavy bombers. The prototype R-4360s delivered a total of 18,000 hp (13,000 kW). While early B-36s required long takeoff runs, this situation was improved with later versions, delivering a significantly increased power output of 22,800 hp (17,000 kW) total.[26] Each engine drove a three-bladed propeller, 19 feet (5.8 m) in diameter, mounted in the pusher configuration, thought to be the second-largest diameter propeller design ever used to power a piston-engined aircraft. This unusual configuration prevented propeller turbulence from interfering with airflow over the wing, but could also lead to engine overheating due to insufficient airflow around the engines, resulting in inflight engine fires.

The large, slow-turning propellers interacted with the high pressure airflow behind the wings to produce an easily recognizable very low frequency pulse at ground level that betrayed approaching flights.

Beginning with the B-36D, Convair added a pair of General Electric J47-19 jet engines suspended near the end of each wing; these were also retrofitted to all extant B-36Bs. Consequently, the B-36 was configured to have ten engines, six radial propeller engines and four jet engines, leading to the B-36 slogan of "six turnin' and four burnin' ". The B-36 had more engines than any other mass-produced aircraft, the jet pods greatly improved takeoff performance and dash speed over the target. In normal cruising flight, the jet engines were shut down to conserve fuel. When the jet engines were shut down, louvers closed off the front of the pods to reduce drag and to prevent ingestion of sand and dirt, the jet engine louvers were opened and closed by the flight crew in the cockpit, whether the B-36 was on the ground or in the air.[27] The two pods with four turbojets and the six piston engines combined gave the B-36 a total of 40,000 hp (30,000 kW) for short periods of time.[28]

The B-36 had a crew of 15, as in the B-29 and B-50, the pressurized flight deck and crew compartment were linked to the rear compartment by a pressurized tunnel through the bomb bay. In the B-36, movement through the tunnel was on a wheeled trolley, pulling on a rope, the rear compartment featured six bunks and a dining galley, and led to the tail turret.[29]

The XB-36 featured a single-wheel main landing gear whose tires were the largest ever manufactured up to that time[irrelevant citation], 9 feet 2 inches (2.79 m) tall, 3 feet (91 cm) wide, and weighing 1,320 pounds (600 kg), with enough rubber for 60 automobile tires.[irrelevant citation][3] These tires placed so much pressure on runways, that the XB-36 was restricted to the Fort Worth airfield adjacent to the plant of manufacture, and to a mere two USAF bases beyond that, at the suggestion of General Henry H. Arnold, the single-wheel gear was soon replaced by a four-wheel bogie.[30] At one point, a tank-like tracked landing gear was also tried on the XB-36, but it proved heavy and noisy, the tracked landing gear was quickly abandoned.

The four bomb bays could carry up to 86,000 pounds (39,000 kg) of bombs, more than 10 times the load carried by the World War II workhorse, the Boeing B-17 Flying Fortress, and substantially more than the entire B-17's gross weight.[31] The B-36 was not designed with nuclear weaponry in mind, because the mere existence of such weapons was top secret during the period when the B-36 was conceived and designed (1941–46). Nevertheless, the B-36 stepped into its nuclear delivery role immediately upon becoming operational; in all respects except speed, the B-36 could match what was arguably its approximate Soviet counterpart, the turboprop-powered Tu-95, which began production in January 1956 and was still in active service as of June 2016[update].[32] Until the B-52 became operational, the B-36 was the only means of delivering the first generation Mark-17 hydrogen bomb,[33] 25 ft (7.6 m) long, 5 ft (1.5 m) in diameter, and weighing 42,000 lb (19,000 kg), the heaviest and bulkiest American aerial nuclear bomb ever. Carrying this massive weapon required merging two adjacent bomb bays.[citation needed]

The defensive armament consisted of six remote-controlled retractable gun turrets, and fixed tail and nose turrets, each turret was fitted with two 20 mm cannons, for a total of 16. Recoil vibration from gunnery practice often caused the aircraft's electrical wiring to jar loose or the vacuum tube electronics to malfunction, leading to failure of the aircraft controls and navigation equipment; this contributed to the crash of B-36B 44-92035 on 22 November 1950.[34]

The Convair B-36 was the only aircraft designed to carry the T-12 Cloudmaker, a gravity bomb weighing 43,600 lb (19,800 kg) and designed to produce an earthquake bomb effect. Part of the testing process involved dropping two of the bombs on a single flight mission, one from 30,000 feet and the second from 40,000 feet, for a total bomb load of 87,200 pounds.

The first prototype XB-36 flew on 8 August 1946, the speed and range of the prototype failed to meet the standards set out by the Army Air Corps in 1941. This was expected, as the Pratt & Whitney R-4360 engines required were not yet available, and there was a lack of the qualified workers and materials needed to install them.[16][35]

A second aircraft, the YB-36, flew on 4 December 1947, it had a redesigned high-visibility, yet still "greenhouse-like" bubble canopy, heavily framed due to its substantial size, which was later adopted for production, and the engines used on the YB-36 were a good deal more powerful and more efficient. Altogether, the YB-36 was much closer to the production aircraft.

The XB-36 on its first flight

The first of 21 B-36As were delivered in 1948, they were interim airframes, intended for crew training and later conversion. No defensive armament was fitted, since none was ready. Once later models were available, all B-36As were converted to RB-36E reconnaissance models, the first B-36 variant meant for normal operation was the B-36B, delivered beginning in November 1948. This aircraft met all the 1941 requirements, but had serious problems with engine reliability and maintenance (changing the 336 spark plugs was a task dreaded by ground crews) and with the availability of armaments and spare parts. Later models featured more powerful variants of the R-4360 engine, improved radar, and redesigned crew compartments.

The four jet engines increased fuel consumption and reduced range, the advent of air-to-air missiles then rendered conventional gun turrets obsolete. In February 1954 the USAF awarded Convair a contract for a new "Featherweight" design program which significantly reduced weight and crew size. There were three configurations:

Featherweight I removed defensive hardware, including the six gun turrets.

The six turrets eliminated by Featherweight I reduced the aircraft's crew from 15 to 9. Featherweight III had a longer range and an operating ceiling of at least 47,000 feet (14,000 m), especially valuable for reconnaissance missions. The B-36J-III configuration (the last 14 made) had a single radar-aimed tail turret, extra fuel tanks in the outer wings, and landing gear allowing the maximum gross weight to rise to 410,000 pounds (190,000 kg).

Due to problems that occurred with the B-36 in its early stages of testing, development and later in service, some critics referred to the aircraft as a "billion-dollar blunder";[37] in particular, the United States Navy saw it as a costly bungle, diverting congressional funding and interest from naval aviation and aircraft carriers in general, and carrier–based nuclear bombers in particular. In 1947, the Navy attacked congressional funding for the B-36, alleging it failed to meet Pentagon requirements, the U.S. Navy held to the preeminence of the aircraft carrier in the Pacific during World War II, presuming carrier-based aircraft would be decisive in future wars. To this end, the Navy designed the USS United States (CVA-58), a "supercarrier" capable of launching huge fleets of tactical aircraft or nuclear bombers. It then pushed to have funding transferred from the B-36 to the USS United States, the Air Force successfully defended the B-36 project, and the United States was officially cancelled by Secretary of DefenseLouis A. Johnson in a cost-cutting move. Several high-level Navy officials questioned the government's decision, alleging a conflict of interest because Johnson had once served on Convair's board of directors, the uproar following the cancellation of United States in 1949 was nicknamed the "Revolt of the Admirals".[38]

The furor, as well as the significant use of aircraft carriers in the Korean War, resulted in the design and procurement of the subsequent Forrestal class of supercarriers, which were of comparable size to the United States, but with a design geared towards greater multirole use with composite air wings of fighter, attack, reconnaissance, electronic warfare, early warning and anti-submarine warfare aircraft. At the same time, heavy manned bombers for the Strategic Air Command were also deemed crucial to national defense and, as a result, the two systems were never again in competition for the same budgetary resources.[39][40]

The B-36, including its GRB-36, RB-36, and XC-99 variants, was in USAF service as part of the Strategic Air Command from 1948 to 1959, the RB-36 variants of the B-36 were used for reconnaissance during the Cold War with the Soviet Union and the B-36 bomber variants conducted training and test operations and stood ground and airborne alert, but the latter variants were never used offensively as bombers against hostile forces; it never fired a shot in combat.[citation needed]

Personnel and equipment required to get and keep a B-36 aircraft in the air

The Wasp Major engines had a prodigious appetite for lubricating oil: each engine required a dedicated 100 gal (380 l) tank.[citation needed] Normal maintenance consisted of tedious measures, such as changing the 56 spark plugs on each of the six engines; the plugs were often fouled by the lead in the 145octane anti-knock fuel required by the R-4360 engines. Thus, each service required changing 336 spark plugs. Another frequent maintenance job was replacing the dozens of bomb bay light bulbs, which routinely shattered during test firing of the turret guns.[citation needed]

The B-36 was too large to fit in most hangars, since even an aircraft with the range of the B-36 needed to be stationed as close to enemy targets as possible, this meant the plane was largely based in the extreme weather locations of the northern continental United States, Alaska and the Arctic. Since the maintenance had to be performed outdoors, the crews were largely exposed to the elements, with temperatures of −60 °F (−51 °C) in winters and 100 °F (38 °C) in summers, depending on the airbase location. Special shelters were built so that the maintenance crews could be given a modicum of protection. Ground crews were at risk of slipping and falling from icy wings, or being blown off the wings by propeller wash running in reverse pitch. The wing roots were thick enough, at 7 ft (2.1 m), to enable a flight engineer to access the engines and landing gear during flight by crawling through the wings. This was possible only at altitudes not requiring pressurization.[41]

In 1950, Convair (then still Consolidated-Vultee) developed streamlined pods, looking like oversize drop tanks, that were mounted on each side of the B-36's fuselage to carry spare engines between bases, each pod could airlift two engines. When the pods were empty, they were removed and carried in the bomb bays. There is no record of the special engine pods ever being used.[42]

As engine fires occurred with the B-36's radial engines, some crews humorously changed the aircraft's slogan from "six turning, four burning" into "two turning, two burning, two smoking, two choking, and two more unaccounted for."[43][N 2] This problem was exacerbated by the propellers' pusher configuration, which increased carburetor icing, the design of the R-4360 engine tacitly assumed that it would be mounted in the conventional tractor configuration—propeller/air intake/28 cylinders/carburetor—with air flowing in that order. In this configuration, the carburetor is bathed in warmed air flowing past the engine, and so is unlikely to ice up. However, the R-4360 engines in the B-36 were mounted backwards, in the pusher configuration—air intake/carburetor/28 cylinders/propeller, the carburetor was now in front of the engine and so could not benefit from engine heat, and also made more traditional short term carburetor heat systems unsuitable[why?]. Hence, when intake air was cold and humid, ice gradually obstructed the carburetor air intake, which in turn gradually increased the richness of the air/fuel mixture until the unburned fuel in the exhaust caught fire.[44] Three engine fires of this nature led to the first loss of an American nuclear weapon when a B-36 crashed in February 1950.

RB-36s in production. Note the heavily-framed "greenhouse" bubble canopy over the cockpit area, used for all production B-36 airframes.

Training missions were typically in two parts: a 40-hour flight—followed by time on the ground for refueling and maintenance—and then a 24-hour second flight, with a sufficiently light load, the B-36 could fly at least 10,000 mi (16,000 km) nonstop, and the highest cruising speed of any version, the B-36J-III, was at 230 mph (380 km/h). Engaging the jet engines could raise the cruising speed to over 400 mph (650 km/h). Hence a 40-hour mission, with the jets used only for takeoff and climbing, flew about 9,200 mi (15,000 km).

Due to its massive size, the B-36 was never considered sprightly or agile; Lieutenant General James Edmundson likened it to "...sitting on your front porch and flying your house around."[45] Crew compartments were nonetheless cramped, especially when occupied for 24 hours by a crew of 15 in full flight kit.

War missions would have been one-way, taking off from forward bases in Alaska or Greenland, overflying the USSR, and landing in Europe, Morocco, or the Middle East. Veteran crews recall feeling confident in their ability to fly the planned missions but not to survive weapon delivery, as the aircraft may not have been fast enough to escape the blast,[46] these concerns were borne out by the 1954 Operation Castle tests, in which B-36s were flown at the combat distance from the detonations of bombs in the 15-megaton range. At distances believed typical of wartime delivery, aircraft suffered extensive flash and blast damage.[47]

The B-36 was employed in a variety of aeronautical experiments throughout its service life, its immense size, range and payload capacity lent itself to use in research and development programs. These included nuclear propulsion studies, and "parasite" programs in which the B-36 carried smaller interceptors or reconnaissance aircraft.[48]

In May 1946, the Air Force began the Nuclear Energy for the Propulsion of Aircraft (NEPA) project, which was followed in May 1951 by the Aircraft Nuclear Propulsion (ANP) program, the ANP program used modified B-36s to study shielding requirements for an airborne reactor to determine whether a nuclear powered aircraft was feasible. Convair modified two B-36s under the MX-1589 project, the Nuclear Test Aircraft (NTA) was a B-36H-20-CF (serial number 51-5712) that had been damaged in a tornado at Carswell AFB on 1 September 1952. This aircraft, designated the XB-36H (and later NB-36H), was modified to carry a 1 MW, air-cooled nuclear reactor in the aft bomb bay, with a four-ton lead disc shield installed in the middle of the aircraft between the reactor and the cockpit. A number of large air intake and exhaust holes were installed in the sides and bottom of the aircraft's rear fuselage to cool the reactor in flight,[49] on the ground, a crane would be utilized to remove the 35,000 pounds (16,000 kg) reactor from the aircraft. To protect the crew, the highly modified cockpit was encased in lead and rubber, with a 1-foot-thick (30 cm) leaded glasswindshield.[49] The reactor was operational, but did not power the aircraft; its sole purpose was to investigate the effect of radiation on aircraft systems. Between 1955 and 1957, the NB-36H completed 47 test flights and 215 hours of flight time, during 89 of which the reactor was critical.[citation needed]

Other experiments involved providing the B-36 with its own fighter defense in the form of parasite aircraft carried partially or wholly in a bomb bay. One parasite aircraft was the diminutive McDonnell XF-85 Goblin, which docked using a trapeze system, the concept was tested successfully using a B-29 carrier, but docking proved difficult even for experienced test pilots. Moreover, the XF-85 was seen as no match for contemporary foreign powers' newly developed interceptor aircraft in development and in service; consequently, the project was cancelled.[50]

More successful was the FICON project, involving a modified B-36 (called a GRB-36D "mothership") and the RF-84K, a fighter modified for reconnaissance, in a bomb bay, the GRB-36D would ferry the RF-84K to the vicinity of the objective, whereupon the RF-84K would disconnect and begin its mission. Ten GRB-36Ds and 25 RF-84Ks were built and saw limited service in 1955–1956.[citation needed]

Projects TIP TOW and Tom-Tom involved docking F-84s to the wingtips of B-29s and B-36s. The hope was that the increased aspect ratio of the combined aircraft would result in a greater range. Project TIP TOW was canceled when an EF-84D and a specially modified test EB-29A crashed, killing everyone on both aircraft, this accident was attributed to the EF-84D flipping over onto the wing of the EB-29A. Project Tom-Tom, involving RF-84Fs and a GRB-36D from the FICON project (redesignated JRB-36F), continued for a few months after this crash, but was also canceled due to the violent turbulence induced by the wingtip vortices of the B-36.[51]

In late 1952 during the Korean War six 5th Strategic Reconnaissance Wing RB-36Ds were deployed to the 91st Strategic Reconnaissance Group. at Yokota AB, Japan. This was the first introduction of RB-36 to the Korean theater. While not employed in any combat missions over North Korea, these RB-36s conducted high altitude aerial reconnaissance over Chinese Manchurian and Soviet east Asian targets while attached to the 91st SRG.[52]

One of the SAC's initial missions was to plan strategic aerial reconnaissance on a global scale, the first efforts were in photo-reconnaissance and mapping. Along with the photo-reconnaissance mission, a small electronic intelligence (ELINT) cadre was operating. Weather reconnaissance was part of the effort, as was Long Range Detection, the search for Soviet atomic explosions; in the late 1940s, strategic intelligence on Soviet capabilities and intentions was scarce. Before the development of the Lockheed U-2 high altitude spy plane and orbital reconnaissance satellites Corona, technology and politics limited American reconnaissance efforts to the borders, and not the heartland, of the Soviet Union.[53]

One of the essential criteria of the early postwar reconnaissance aircraft was the ability to cruise above 40,000 feet (12,000 m), a level determined by knowledge of the capability of Soviet air defense radar. The main Soviet air defense radar in the 1950s was the American supplied SCR-270, or locally made copies, which were only effective up to 40,000 feet (12,000 m) – in theory, an aircraft cruising above this level would remain undetected.[54]

The first aircraft to put this theory to the test was the RB-36D specialized photographic-reconnaissance version of the B-36D, it was outwardly identical to the standard B-36D, but carried a crew of 22 rather than 15, the additional crew members being needed to operate and maintain the photographic reconnaissance equipment that was carried. The forward bomb bay in the bomber was replaced by a pressurized manned compartment that was filled with fourteen cameras, this compartment included a small darkroom where a photo technician could develop the film. The second bomb bay contained up to 80 T-86 photoflash bombs, while the third bay could carry an extra 11,000 litres (3,000 US gal) droppable fuel tank. The fourth bomb bay carried electronic countermeasure (ECM) equipment, the defensive armament of 16 M-24A-1 20 mm cannons was retained. The extra fuel tanks increased the flight endurance to up to 50 hours. It had an operational ceiling of 50,000 feet (15,000 m). Later, a lightweight version of this aircraft, the RB-36-III, could even reach 58,000 ft (18,000 m). RB-36s were distinguished by the bright aluminium finish of the camera compartment (contrasting with the dull magnesium of the rest of the fuselage) and by a series of radar domes under the aft fuselage, varying in number and placement. When developed, it was the only American aircraft having enough range to fly over the Eurasian land mass from bases in the United States, and size enough to carry the bulky high resolution cameras of the day.[55]

The first RB-36D (44-92088) made its initial flight on 18 December 1949, only six months after the first B-36D had flown, it initially flew without the turbojets. The 28th Strategic Reconnaissance Wing based at Rapid City AFB (later renamed Ellsworth AFB), South Dakota received its first RB-36D on 3 June 1950. Due to severe material shortages, the new RB-36Ds did not become operationally ready until June 1951, the 24th and last RB-36D was delivered in May 1951. A total of 24 RB-36Ds were built, some RB-36Ds were later modified to the featherweight configuration, in which all but the tail guns were removed. The crew was reduced from 22 to 19, these aircraft were redesignated as RB-36D-III. Modifications were carried out by Convair from February 1954 to November 1954.[55]

With a range of 9,300 miles (15,000 km), RB-36Ds began probing the boundaries of the Soviet Arctic in 1951. Although on-board equipment indicated detection by Soviet radar, interceptions at the B-36's service ceiling would have remained difficult. RB-36 aircraft operating from RAF Sculthorpe in England made a number of overflights of Soviet Arctic bases, particularly the new nuclear weapons test complex at Novaya Zemlya. RB-36s performed a number of rarely acknowledged reconnaissance missions and are believed to have frequently penetrated Chinese (and Soviet) airspace under the direction of General Curtis LeMay.[54]

In early 1950, Convair began converting B-36As to a reconnaissance configuration; included in the conversions was the sole YB-36 (42-13571). These converted examples were all redesignated RB-36E, the six R-4360-25 engines were replaced by six R-4360-41s. They were also equipped with the four J-47 jet engines that were fitted to the RB-36D, its normal crew was 22, which included five gunners to man the 16 M-24A-1 20 mm cannon. The last conversion was completed in July 1951. Later, the USAF also bought 73 long-range reconnaissance versions of the B-36H under the designation RB-36H. 23 were accepted during the first six months of 1952, the last were delivered by September 1953. More than a third of all B-36 models were reconnaissance models.[55]

Advances in Soviet air defense systems meant that the RB-36 became limited to flying outside the borders of the Soviet Union, as well as Eastern Europe. By the mid-1950s, the jet-powered Boeing RB-47E was able to pierce Soviet airspace and conduct a variety of spectacular overflights of the Soviet Union, some of these flights probed deep into the heart of the Soviet Union, taking a photographic and radar recording of the route attacking SAC bombers would follow to reach their targets. Flights which involved penetrating mainland Russia were termed SENSINT (Sensitive Intelligence) missions. One RB-47 flew 450 miles (720 km) inland and photograph the city of Igarka in Siberia.[54]

As with the strategic bombardment versions of the B-36, the RB-36s were phased out of the SAC inventory beginning in 1956, the last being sent to Davis–Monthan Air Force Base in January 1959.

With the appearance of the Soviet Mikoyan-Gurevich MiG-15 in combat over North Korea in 1950, USAF propeller-driven bombers were rendered obsolete as strategic offensive weapons, during daylight, the MiG-15 could, and did, attack the propeller-driven B-29s, forcing the U.S. to switch the B-29 to night raids.[citation needed]

The B-36, along with the B-29/B-50 Superfortresses in the USAF inventory in the early 1950s, were all designed during World War II prior to the jet age, it would take a new generation of swept-wing jet bombers, able to fly higher and faster, to effectively overcome defense by MiG-15 or subsequent Soviet-designed interceptors if the Cold War escalated into an armed conflict between the United States and Soviet Union.[citation needed]

The two main factors contributing to the obsolescence of the B-36 and leading to its phaseout[citation needed] were:

The Peacemaker was not designed for aerial refueling, and required intermediate refueling bases to reach its planned targets deep in the Soviet Union.[citation needed]

Its slow speed made it vulnerable to Soviet jet interceptor aircraft, making long-range bombardment flights over Soviet territory extremely hazardous, seriously compromising its ability to reach its planned target and return.[citation needed]

The scrapping of B-36s began in February 1956. Once replaced by B-52s, they were flown directly from operational squadrons to Davis–Monthan AFB, Arizona, where the Mar-Pak Corporation handled their reclamation and destruction. Defense cutbacks in FY 1958 compelled the B-52 procurement process to be stretched out and the B-36 service life to be extended, the B-36s remaining in service were supported with components scavenged from aircraft sent to Davis–Monthan. Further update work was undertaken by Convair at San Diego (Specialized Aircraft Maintenance, SAM-SAC) until 1957 to extend the life and capabilities of the B-36s. By December 1958 only 22 B-36Js were still operational.[55]

In 1951, the USAF asked Convair to build a prototype of an all-jet variant of the B-36. Convair complied by replacing the wings on a B-36F with swept wings, from which were suspended eight Pratt & Whitney XJ57-P-3 jet engines. The result was the B-36G, later renamed the Convair YB-60, the YB-60 was deemed inferior to Boeing's YB-52, and the project was terminated.[59] Just as the C-97 was the transport variant of the B-50, the B-36 was the basis for the Convair XC-99, a double-decked military cargo plane that was the largest piston engined, land-based aircraft ever built, and the longest practical aircraft (185 ft/56 m) of its era. The sole example built was extensively employed for nearly 10 years, especially for cross-country cargo flights during the Korean War; in 2005, this XC-99 was dismantled in anticipation of its being moved from the former Kelly Air Force Base, now the Kelly Field Annex of Lackland AFB in San Antonio, Texas, where it had been retired since 1957. The XC-99 was subsequently relocated to the National Museum of the United States Air Force at Wright-Patterson Air Force Base near Dayton, Ohio for restoration, with C-5 Galaxy transports carrying pieces of the XC-99 to Wright-Patterson as space and schedule permitted.[60]

A commercial airliner derived from the XC-99, the Convair Model 37, never left the drawing board, it would have been the first "jumbo" airliner.[3]

Only four complete (and one stored) B-36 type aircraft survive (as of 2004), from the 384 produced.[62]

YB-36/RB-36E

AF Ser. No. 42-13571 – in the private collection of the late Walter Soplata in Newbury, Ohio.[63] This was the first prototype to be converted to the bubble canopy used on production B-36s, it was on display in the 1950s and 1960s at the former site of the Air Force Museum, now the National Museum of the United States Air Force, at Wright-Patterson Air Force Base near Dayton, Ohio. When the museum's current location at Wright-Patterson was being developed in the late 1950s, the cost of moving the bomber was more than simply flying a different B-36 to the new location and the aircraft was slated to be scrapped, it was cut up at the old museum site by August 1972. Instead of being completely disposed of, Soplata bought it and transported the pieces by truck to his farm, where it sits today, the bomb bay currently contains a complete P-47N still packed in its original shipping crate.[64]

AF Ser. No. 52-2220 – National Museum of the United States Air Force (NMUSAF), formerly The U.S. Air Force Museum, at Wright-Patterson Air Force Base near Dayton, Ohio. Its flight to the museum from Davis–Monthan Air Force Base in Arizona on 30 April 1959 was the last flight of a B-36, this B-36J replaced the former Air Force Museum's original YB-36, AF Serial Number 42-13571 (see above). This was also the first aircraft to be placed in the Museum's new display hangar, and was not moved again until relocated to the Museum's latest addition in 2003, it is displayed alongside the only surviving example of the massive 9 ft (2.7 m) lower main gear strut, single wheel and tire that was used on the original XB-36.[67]

Though the B-36 had a solid overall safety record, well above average for the class and time, a total of ten B-36s were involved in accidents between 1949 and 1954 (three B-36Bs, three B-36Ds, and four B-36Hs).[69] A total of 32 B-36s were written off in accidents between 1949 and 1957 of 385 built.[70] When a crash occurred, the magnesium-rich airframe burned easily.[71]

On Labor Day, Monday, 1 September 1952, a tornado hit Carswell Air Force Base, Fort Worth, Texas damaging aircraft of the 7th and 11th Bomber Wings' complement of B-36s, some two thirds of the USAF's entire B-36 fleet were affected, as well as six aircraft being built at that point at Convair's Fort Worth plant. The base was shut down and operations transferred to Meacham Field. Joint repairs by Convair and the USAF got ten of the 61 B-36s running within two weeks and repaired the other 51 aircraft within five weeks. 18 of 19 heavily damaged aircraft (and the six damaged and unfinished aircraft at Convair) were repaired by May 1953. The 19th (#2051) had to be scrapped, and was used as a nuclear testing site ground target. One heavily damaged aircraft (#5712) was written off and rebuilt as the NB-36H Nuclear Reactor Testbed aircraft.[72]

Official US Air Force accident incident photo of the 18 March 1953 crash

B-36s were involved in two "Broken Arrow" incidents, on 13 February 1950, B-36 serial number 44-92075, crashed in an unpopulated region of British Columbia, resulting in the first loss of an American atom bomb. The bomb's plutonium core was dummy lead, but it did have TNT, and it detonated over the ocean before the crew bailed out.[73] Locating the crash site took some effort,[74] on 4 November 2016, however, it was reported that an object similar to the bomb had been located by a diver near the archipelago of Haida Gwaii, 80 km (50 mi) off the coast of British Columbia; the Royal Canadian Navy said vessels would be deployed to investigate the object.[75] After investigation, the Royal Canadian Navy determined that it was not the lost bomb.[76] Later in 1954, the airframe, stripped of sensitive material, was substantially destroyed in situ by a U.S. military recovery team.

Throughout its time in service, the B-36 was the subject of USAF lore, some apocryphal, some containing a grain of truth.

"If all engines function normally at full power during the pre-takeoff warm-up, the lead flight engineer will sometimes say to the AC (Aircraft Commander), 'six turning and four burning.' Erratic reliability led to the wisecrack, 'two turning, two burning, two joking, and two smoking, with two engines not accounted for.'"

The documentary Lost Nuke (2004) chronicles a 2003 Canadian expedition that set out to solve the mystery of the world's first lost nuclear weapon, the team traveled to the remote mountain site of the 1950 British Columbia B-36 crash.[80]

^Convair proposed the name "Peacemaker" in a submission to a contest to name the bomber. Although the name "Peacemaker" was not officially adopted, it was commonly used and sources often state or imply the name is "official".[2]

^Quote attributed to Captain Banda when he was escorting Air Cadet Michael R. Daciek, later Lieutenant Colonel Daciek, on an inside tour of the XC-99 in 1953.

^"Weapons of Mass Destruction – Systems – Bombers – B-36". globalsecurity.org. GlobalSecurity.org. Retrieved December 12, 2016. Ensuing talks between Secretary of War Henry L. Stimson, Assistant Secretary of War Robert P. Patterson, and high ranking officers of the AAF, led Secretary Stimson to waive customary procurement procedures and to authorize the AAF to order B-36 production without awaiting completion and testing of the 2 experimental planes then under contract. Therefore, on 19 June General Arnold directed procurement of 100 B-36s. General Arnold became Commanding General of the AAF in March 1942 and was promoted to 4 star general 1 year later, his order, however, would be cut back or canceled in the event of excessive production difficulties. The AAF letter of intent for 100 B-36s was signed by Convair on 23 July, the letter of intent of 23 July 1943, supplemented by Letter Contract W33-038 ac-7 on 23 August 1943, gave way 1 year later to a definitive contract. Interestingly, the US. Government was not liable should a letter of intent be canceled, this was not so for the more often used letter contract which obligated funds.

1.
Strategic bomber
–
In addition to strategic bombing, strategic bombers can be used for tactical missions. There are three countries including United States, Russia, and China are operating strategic bombers, the modern strategic bomber role appeared after strategic bombing was widely employed, and atomic bombs were first used in combat during World War II. An example is Frances Mirage IV, a strategic bomber replaced in service by the ASMP-equipped Mirage 2000N fighter-bomber. Study of strategic bombing continued in the interwar years and it was widely believed by the late 1930s that strategic terror bombing of cities in any war would quickly result in devastating losses and might decide a conflict in a matter of days or weeks. But theory far exceeded what most air forces could actually put into the air, Germany focused on short-range tactical bombers. Britains Royal Air Force began developing four-engine long-range bombers only in the late 1930s, the U. S. Army Air Corps was severely limited by small budgets in the late 1930s, and only barely saved the B-17 bomber that would soon be vital. The equally important B-24 first flew in 1939, both aircraft would constitute the bulk of the American bomber force that made the Allied daylight bombing of Nazi Germany possible in 1943–45. Both Britain and the U. S. were developing larger two- and four-engined designs, after American entry into the war, late, in 1941, the U. S. 8th Air Force began to develop a daylight bombing capacity using improved B-17 and B-24 four-engine aircraft. The RAF concentrated its efforts on night bombing, but neither force was able to develop adequate bombsights or tactics to allow for often-bragged pinpoint accuracy. The post-war U. S. Strategic Bombing Survey studies supported the notion of strategic bombing. Attempts to create pioneering examples of smart bombs resulted in the Azon ordnance, deployed in the European Theater, most strategic bombers of the two superpowers were designed to deliver nuclear weapons. For a time, some squadrons of Boeing B-52 Stratofortress bombers were kept in the air around the clock, the Royal Air Forces British-produced V bombers were designed and designated to be able to deliver British-made nuclear bombs to targets in European Russia. These bombers could have been able to reach and destroy cities like Kiev or Moscow before American strategic bombers, the Soviet Union produced hundreds of unlicensed, reverse-engineered copies of the American Boeing B-29 Superfortress, which the Soviet Air Forces called the Tupolev Tu-4. The Soviets later developed the jet-powered Tupolev Tu-16 Badger, the Peoples Republic of China produced a version of Tupolev Tu-16 on license from the Soviet Union in the 1960s which they named the Xian H-6, it remains in service today. Mirage IVs served until mid-1996 in the role, and to 2005 as a reconnaissance aircraft. Today the French Republic has limited its strategic armaments to a squadron of four nuclear-powered ballistic missile submarines, france also maintains an active force of supersonic fighter-bombers carrying stand-off nuclear missiles such as the ASMP, with Mach 3 speed and a range of 500 kilometers. These missiles can be delivered by the Dassault Mirage 2000N and Rafale fighter-bombers and it is likely that this bomber would also serve as a replacement for both the B-52 and B-1. The Russian Air Forces new Tu-160 strategic bombers are expected to be delivered on a regular basis over the course of 10 to 20 years, in addition, the current Tu-95 and Tu-160 bombers will be periodically updated, as was done during the 1990s with the Tu-22M bombers

2.
Convair
–
Convair was an American aircraft manufacturing company which later expanded into rockets and spacecraft. It also manufactured the first Atlas rockets, including the rockets that were used for the manned flights of Project Mercury. The companys subsequent Atlas-Centaur design continued this success and derivatives of the remain in use as of 2010. In 1994 most of the divisions were sold by then-owners General Dynamics to McDonnell Douglas and Lockheed. Navy, the Royal Canadian Air Force, the British flying forces, the Catalina remained in production through May 1945, and more than 4,000 were built. What was soon to be called Convair, was created in 1943 by the merger of the Consolidated Aircraft Company and the Vultee Aircraft Company. Convair always had most of its research, design, and manufacturing operations in San Diego County of Southern California, the Convair B-36 was the largest landbased piston engined bomber in the world. The Atlas missile, the F-102 Delta Dagger and F-106 Delta Dart delta-winged interceptors, and the delta-winged B-58 Hustler supersonic intercontinental nuclear bomber were all Convair products. For a period of time in the 1960s, Convair manufactured its own line of jet airliners, the Convair 880 and Convair 990. The Convair Division produced its own designs, such as several airliners, until 1965. In the 1950s Convair shifted money and effort into its missile and rocket projects, convairs Atlas rocket was originally developed in 1957 as an ICBM for the U. S. Air Force. It was replaced in 1962 by the room-temperature liquid-fueled Titan II missile, the Atlas rocket transitioned into a civilian launch vehicle and was used for the first orbital manned U. S. space flights during Project Mercury in 1962 and 1963. The S-IVB had earlier also used as the second stage of the smaller Saturn IB rocket. In 1994, the General Dynamics Corporation split and sold the original Convair Division, the airframe/aerostructures manufacturing company and the space boosters company were sold to the McDonnell Douglas Corporation. S. In 1996, General Dynamics deactivated all of the legal entities of the Convair Division. 1923 Consolidated Aircraft Corporation formed by Major Reuben H. S, Air Force and U. S. Navy aircraft designations that begin with X are merely experimental models of aircraft made only in small numbers. Military aircraft designations that begin with Y are developmental models made in small batches, in the former designation system that the Navy and the Marine Corps used, a final letter of Y identified a Convair or a Consolidated product, such as the PBY-5 flying boat. Centaur BGM-109 Tomahawk long-range, all-weather, subsonic cruise missile, aGM-129 Advanced Cruise Missile – stealthy, nuclear, air-launched cruise missile Convair Drive at the Toronto Pearson International Airport is believed to be named for the Convair company

3.
United States dollar
–
The United States dollar is the official currency of the United States and its insular territories per the United States Constitution. It is divided into 100 smaller cent units, the circulating paper money consists of Federal Reserve Notes that are denominated in United States dollars. The U. S. dollar was originally commodity money of silver as enacted by the Coinage Act of 1792 which determined the dollar to be 371 4/16 grain pure or 416 grain standard silver, the currency most used in international transactions, it is the worlds primary reserve currency. Several countries use it as their currency, and in many others it is the de facto currency. Besides the United States, it is used as the sole currency in two British Overseas Territories in the Caribbean, the British Virgin Islands and Turks and Caicos Islands. A few countries use the Federal Reserve Notes for paper money, while the country mints its own coins, or also accepts U. S. coins that can be used as payment in U. S. dollars. After Nixon shock of 1971, USD became fiat currency, Article I, Section 8 of the U. S. Constitution provides that the Congress has the power To coin money, laws implementing this power are currently codified at 31 U. S. C. Section 5112 prescribes the forms in which the United States dollars should be issued and these coins are both designated in Section 5112 as legal tender in payment of debts. The Sacagawea dollar is one example of the copper alloy dollar, the pure silver dollar is known as the American Silver Eagle. Section 5112 also provides for the minting and issuance of other coins and these other coins are more fully described in Coins of the United States dollar. The Constitution provides that a regular Statement and Account of the Receipts and that provision of the Constitution is made specific by Section 331 of Title 31 of the United States Code. The sums of money reported in the Statements are currently being expressed in U. S. dollars, the U. S. dollar may therefore be described as the unit of account of the United States. The word dollar is one of the words in the first paragraph of Section 9 of Article I of the Constitution, there, dollars is a reference to the Spanish milled dollar, a coin that had a monetary value of 8 Spanish units of currency, or reales. In 1792 the U. S. Congress passed a Coinage Act, Section 20 of the act provided, That the money of account of the United States shall be expressed in dollars, or units. And that all accounts in the offices and all proceedings in the courts of the United States shall be kept and had in conformity to this regulation. In other words, this act designated the United States dollar as the unit of currency of the United States, unlike the Spanish milled dollar the U. S. dollar is based upon a decimal system of values. Both one-dollar coins and notes are produced today, although the form is significantly more common

4.
Convair XC-99
–
43-52436, is a prototype heavy cargo aircraft built by Convair for the United States Air Force. It was the largest piston-engined land-based transport aircraft built, and was developed from the Convair B-36 bomber, sharing the wings. The first flight was on 24 November 1947 in San Diego, California, the Convair Model 37 was a planned civil passenger variant based on the XC-99 but was not built. Design capacity of the XC-99 was 100,000 lb of cargo or 400 fully equipped troops on its double cargo decks, a cargo lift was installed for easier loading. The engines face rearward in a pusher configuration, the Convair Model 37 was a large civil passenger design derived from the XC-99 but was never built. The Model 37 was to be of similar proportions to the XC-99,182 ft 6 in length,230 ft wingspan, the projected passenger load was to be 204, and the effective range of 4,200 mi. Fifteen aircraft were ordered by Pan American Airways for transatlantic service, the low number of orders were not sufficient to initiate production, and the project was abandoned. In July 1950, the XC-99 flew its first cargo mission, Operation Elephant. In August 1953, the XC-99 would make its longest flight,12,000 mi, to Rhein-Main Air Base, Germany, by way of Kindley Air Force Base, Bermuda and it carried more than 60,000 lb each way. It attracted much attention everywhere it flew, the US Air Force determined that it had no need for such a large, long-range transport at that time, and no more were ordered. The sole XC-99 served until 1957, including much use during the Korean War, during its operational life, the XC-99 logged over 7,400 hours total time, and transported more than 60 million pounds of cargo. The aircraft made its last flight on 19 March 1957, landing at Kelly Air Force Base, the aircraft was put on display at Kelly Air Force Base near San Antonio, Texas, in 1957. Deterioration of the due to the high magnesium content was beyond local abilities to address. The aircraft was moved to a grassy field near the base. By the summer of 2008, the transfer was complete and the parts were lying outside the museum, some major components such as the wing spar would need to be completely replaced. The NMUSAFs plans for the restoration and display of the XC-99 are displayed in a case with a 1,72 scale model made by Lt Col Howard T. Meek, USAF. In 2014, Lieutenant General John L. Hudson, USAF, 43-52436 is part of the National Museum of the United States Air Force collection at Wright-Patterson AFB in Dayton, Ohio. The aircraft was disassembled at Kelly Air Force Base, Texas and its sections transported to NMUSAF for anti-corrosion preservation and reassembly there. S

5.
Nuclear weapon
–
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from small amounts of matter. The first test of a bomb released the same amount of energy as approximately 20,000 tons of TNT. The first thermonuclear bomb test released the same amount of energy as approximately 10 million tons of TNT, a thermonuclear weapon weighing little more than 2,400 pounds can produce an explosive force comparable to the detonation of more than 1.2 million tons of TNT. A nuclear device no larger than traditional bombs can devastate a city by blast, fire. Nuclear weapons are considered weapons of destruction, and their use. Nuclear weapons have been used twice in nuclear warfare, both times by the United States against Japan near the end of World War II, the bombings resulted in the deaths of approximately 200,000 civilians and military personnel from acute injuries sustained from the explosions. The ethics of the bombings and their role in Japans surrender remain the subject of scholarly, since the atomic bombings of Hiroshima and Nagasaki, nuclear weapons have been detonated on over two thousand occasions for the purposes of testing and demonstration. Only a few nations possess such weapons or are suspected of seeking them, israel is also believed to possess nuclear weapons, though in a policy of deliberate ambiguity, it does not acknowledge having them. Germany, Italy, Turkey, Belgium and the Netherlands are nuclear weapons sharing states, south Africa is the only country to have independently developed and then renounced and dismantled its nuclear weapons. Modernisation of weapons continues to occur, all existing nuclear weapons derive some of their explosive energy from nuclear fission reactions. Weapons whose explosive output is exclusively from fission reactions are commonly referred to as bombs or atom bombs. This has long noted as something of a misnomer, as their energy comes from the nucleus of the atom. The latter approach is considered more sophisticated than the former and only the approach can be used if the fissile material is plutonium. A major challenge in all nuclear weapon designs is to ensure that a significant fraction of the fuel is consumed before the weapon destroys itself. The amount of energy released by fission bombs can range from the equivalent of just under a ton to upwards of 500,000 tons of TNT, all fission reactions necessarily generate fission products, the radioactive remains of the atomic nuclei split by the fission reactions. Many fission products are highly radioactive or moderately radioactive. Fission products are the radioactive component of nuclear fallout

6.
Strategic Air Command
–
At a lower echelon, headquarters divisions included Aircraft Engineering, Missile Concept, and Strategic Communications. In 1992, as part of an overall post-Cold War reorganization of the U. S. Planning to reorganize for a separate and independent postwar U. S. Air Force had begun by the fall of 1945, with the Simpson Board tasked to plan. the reorganization of the Army, SAC initially totaled 37,000 USAAF personnel. S. Air Force as an independent service, kenney, initial units reporting to the Strategic Air Command headquarters on 21 March 1946 included the Second Air Force, the IX Troop Carrier Command and the 73d Air Division. In addition to the bombing mission, SAC also devoted significant resources to aerial reconnaissance. An F-13 squadron, the F-13 later re-designated as the RB-29 Superfortress, was also established, SAC conducted routine aerial reconnaissance missions near the Soviet borders or near the 12-mile international waters limit, although some missions actually penetrated into Soviet airspace. The flight profiles of these missions—above 30,000 feet and in excess of 300 knots—made interception by Soviet air forces difficult until the Soviets 1948 introduction of the MiG-15 jet fighter. Project Nanook, the Cold War’s first Top Secret reconnaissance effort, used the first RB-29 missions for mapping and visual reconnaissance in the Arctic, later missions were Project LEOPARD along the Chukchi Peninsula, followed by Projects RICKRACK, STONEWORK, and COVERALLS. In 1946, the US possessed only nine atomic bombs and twenty-seven B-29s capable at any one time of delivering them, unfortunately, postwar budget and personnel cuts had had an insidious effect on SAC as its Deputy Commander, Major General Clements McMullen, implemented mandated force reductions. This continued to wear down SAC as a command and morale plummeted, as a result, by the end of 1947, only two of SACs eleven groups were combat ready. In terms of overall Air Force basing and infrastructure, SAC continued to acquire a share of USAF infrastructure. In 1947, before the USAF was established as an independent service, construction commenced on Limestone AAF, Maine, fort Dix AAF, New Jersey, Spokane AAF, Washington, and Wendover Field, Utah were also transferred to SAC between 30 April and 1 September 1947. Following establishment of the USAF as a service, SAC bases in the United States consisted of

7.
Boeing B-52 Stratofortress
–
The Boeing B-52 Stratofortress is an American long-range, subsonic, jet-powered strategic bomber. The B-52 was designed and built by Boeing, which has continued to provide support and it has been operated by the United States Air Force since the 1950s. The bomber is capable of carrying up to 70,000 pounds of weapons, the B-52 took its maiden flight in April 1952. Built to carry weapons for Cold War-era deterrence missions, the B-52 Stratofortress replaced the Convair B-36. A veteran of wars, the B-52 has dropped only conventional munitions in combat. The B-52s official name Stratofortress is rarely used, informally, the aircraft has become referred to as the BUFF. The B-52 has been in service with the USAF since 1955. As of December 2015,58 were in service with 18 in reserve. The B-52 completed sixty years of service with its original operator in 2015. After being upgraded between 2013 and 2015, it is expected to serve into the 2040s, the aircraft was to have a crew of five or more turret gunners, and a six-man relief crew. It was required to cruise at 300 mph at 34,000 feet with a radius of 5,000 miles. The armament was to consist of a number of 20 mm cannon and 10,000 pounds of bombs. On 13 February 1946, the Air Force issued bid invitations for these specifications, with Boeing, Consolidated Aircraft, and Glenn L. Martin Company submitting proposals. On 5 June 1946, Boeings Model 462, an aircraft powered by six Wright T35 turboprops with a gross weight of 360,000 pounds. On 28 June 1946, Boeing was issued a letter of contract for US$1.7 million to build a full-scale mock-up of the new XB-52 and do preliminary engineering and testing. However, by October 1946, the air began to express concern about the sheer size of the new aircraft. In response, Boeing produced Model 464, a smaller version with a 230,000 pound gross weight. Boeing responded with two powered by the T-35 turboprops

8.
Battle of Britain
–
The Battle of Britain was a military campaign of the Second World War, when the Royal Air Force defended the United Kingdom against the German Air Force attacks from the end of June 1940. It is described as the first major campaign fought entirely by air forces, the primary objective of the Nazi German forces was to compel Britain to agree to a negotiated peace settlement. In July 1940, the air and sea blockade began with the Luftwaffe mainly targeting coastal shipping convoys, ports and shipping centres, such as Portsmouth. On 16 July Hitler ordered the preparation of Operation Sea Lion as an amphibious and airborne assault on Britain. Nazi Germany was unable to sustain daylight raids, but their continued night bombing operations on Britain became known as the Blitz. Its first Chief of the Air Staff Hugh Trenchard was among the military strategists in the 1920s like Giulio Douhet who saw air warfare as a new way to overcome the stalemate of trench warfare, interception was near impossible with fighter planes no faster than bombers. Their view was that the bomber will always get through, Germany was forbidden military air forces by the 1919 Treaty of Versailles, but developed aircrew training in civilian and sport flying. In 1926 the secret Lipetsk fighter-pilot school began operating, a winter 1933–34 war game indicated a need for fighters and anti-aircraft protection as well as bombers. On 1 March 1935 the Luftwaffe was formally announced, with Walther Wever as Chief of Staff, the list excluded bombing civilians to destroy homes or undermine morale, as that was considered a waste of strategic effort, but the doctrine allowed revenge attacks if German civilians were bombed. A revised edition was issued in 1940, and the central principle of Luftwaffe doctrine was that destruction of enemy armed forces was of primary importance. In the Spanish Civil War, the Luftwaffe in the Condor Legion tried out air fighting tactics, wolfram von Richthofen become an exponent of air power providing ground support to other services. The difficulty of hitting targets prompted Ernst Udet to require that all new bombers had to be dive bombers. Priority was given to producing large numbers of aeroplanes. The speed with which German forces defeated most of the armies in Norway in early 1940 created a significant political crisis in Britain. In early May 1940, the Norway Debate questioned the fitness for office of the British Prime Minister Neville Chamberlain, on 10 May, the same day Winston Churchill became British Prime Minister, the Germans initiated the Battle of France with an aggressive invasion of French territory. The Germans were so convinced of an imminent armistice that they began constructing street decorations for the parades of victorious troops. Instead, Churchill used his skilful rhetoric to harden public opinion against capitulation, the Battle of Britain has the unusual distinction that it gained its name before being fought. In secret conference on 23 May 1939 Hitler set out his rather contradictory strategy that an attack on Poland was essential, if this is impossible, then it will be better to attack in the West and to settle Poland at the same time with a surprise attack

9.
The Blitz
–
By September 1940—two months into the battle—faulty German intelligence suggested that the Royal Air Force was close to defeat at the hands of the Luftwaffe. The German air fleets were ordered to attack London, thereby drawing up the last remnants of RAF Fighter Command into a battle of annihilation, Adolf Hitler and commander-in-chief of the Luftwaffe Reichsmarschall Hermann Göring, sanctioned the change in emphasis on 6 September 1940. From 7 September 1940, one year into the war, London was systematically bombed by the Luftwaffe for 56 out of the following 57 days, on 15 September 1940, a large daylight attack against London was repulsed with significant German losses. Thereafter, the Luftwaffe gradually decreased daylight operations in favour of nocturnal attacks, ports and industrial centres outside London were also attacked. The main Atlantic sea port of Liverpool was bombed, the North Sea port of Hull, a convenient and easily found target or secondary target for bombers unable to locate their primary targets, was subjected to raids in the Hull Blitz during the war. More than one million London houses were destroyed or damaged and more than 40,000 civilians were killed, by May 1941, the threat of an invasion of Britain had ended, and Hitlers attention turned to Operation Barbarossa, the invasion of the Soviet Union. The bombing failed to demoralise the British into surrender or significantly damage the war economy, the eight months of bombing never seriously hampered British production and the war industries continued to operate and expand. The German offensives greatest effect was forcing the dispersal of aircraft production, British wartime studies concluded that cities generally took 10 to 15 days to recover when hit severely but exceptions like Birmingham took three months. The German air offensive failed for several reasons, discussions in OKL revolved around tactics rather than strategy. Poor intelligence on British industry and economic efficiency was also a factor, in the 1920s and 1930s, air power theorists Giulio Douhet and Billy Mitchell espoused the idea that air forces could win wars, without a need for land and sea fighting. It was thought there was no defence against air attack, particularly at night, enemy industry, seats of government, factories and communications could be destroyed, taking away their means to resist. It was also thought the bombing of residential centres would cause a collapse of civilian will, democracies, where the populace was allowed to show overt disapproval of the state, were thought particularly vulnerable. This thinking was prevalent in both the RAF and the United States Army Air Corps, the policy of RAF Bomber Command became an attempt to achieve victory through the destruction of civilian will, communications and industry. In the Luftwaffe, there was a view of strategic bombing. OKL did not believe that air power alone could be decisive, contrary to popular belief, evidence suggests that the Luftwaffe did not adopt an official bombing policy in which civilians became the primary target until 1942. The vital industries and transport centres that would be targeted for shutdown were valid military targets and it could be claimed civilians were not to be targeted directly, but the breakdown of production would affect their morale and will to fight. German legal scholars of the 1930s carefully worked out guidelines for what type of bombing was permissible under international law. Wever outlined five points of air strategy, To destroy the air force by bombing its bases and aircraft factories

10.
United States Army Air Corps
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The United States Army Air Corps was the military aviation arm of the United States of America between 1926 and 1941. The USAAC was renamed from the earlier United States Army Air Service on 2 July 1926, the Air Corps became the United States Army Air Forces on 20 June 1941, giving it greater autonomy from the Armys middle-level command structure. The separation of the Air Corps from control of its combat units caused problems of unity of command that became more acute as the Air Corps enlarged in preparation for World War II. This was resolved by the creation of the Army Air Forces, the U. S. Army Air Service had a brief but turbulent history. In early 1926 the Military Affairs Committee of the Congress rejected all bills set forth before it on both sides of the issue. They fashioned a compromise in which the findings of the Morrow Board were enacted as law, while providing the air arm a five-year plan for expansion and development. The legislation changed the name of the Air Service to the Air Corps, thereby strengthening the conception of military aviation as an offensive, the Air Corps Act became law on 2 July 1926. Two additional brigadier generals would serve as assistant chiefs of the Air Corps, previous provisions of the National Defense Act of 1920 that all flying units be commanded only by rated personnel and that flight pay be awarded were continued. The Air Corps also retained the Prop and Wings as its branch insignia through its disestablishment in 1947, patrick became Chief of the Air Corps and Brig. Gen. James E. Fechet continued as his first assistant chief. The Air Corps Act of 2 July 1926 effected no fundamental innovation, the change in designation meant no change in status, the Air Corps was still a combatant branch of the Army with less prestige than the Infantry. The Air Corps Act gave authorization to carry out an expansion program. However, a lack of appropriations caused the beginning of the program to be delayed until 1 July 1927. The act authorized expansion to 1,800 airplanes,1,650 officers, none of the goals were reached by July 1932. Organizationally the Air Corps doubled from seven to fifteen groups, but the expansion was meaningless because all were seriously understrength in aircraft and pilots. Air Corps groups added 1927–1937 ¹Inactivated on 20 May 1937 ²Redesignated 17th Attack Group, 17th Bomb Group As units of the Air Corps increased in number, so did higher command echelons. The 1st Bomb Wing was activated in 1931, followed by the 3rd Attack Wing in 1932 to protect the Mexican border, the three wings became the foundation of General Headquarters Air Force upon its activation in 1935. In 1927 the Air Corps adopted a new scheme for painting its aircraft. The wings and tails of aircraft were painted yellow, with the words U. S

11.
European theatre of World War II
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The Allied forces fought the Axis powers on two major fronts as well as in the adjoining Mediterranean and Middle East Theatre. Germany was humiliated in front of the world and had to pay very large war reparations, many Germans blamed their countrys post-war economic collapse and hyperinflation on the treatys conditions. After Hitler took Germany out of the League of Nations, Mussolini of Fascist Italy and Hitler formed the Rome-Berlin axis, later, Empire of Japan, under the government of Hideki Tojo, would also join as an Axis power. Japan and Germany had already signed the Anti-Comintern Pact in 1939, other smaller powers also later joined the Axis throughout the war. On September 17, the Soviet forces joined the invasion of Poland, the Polish government evacuated the country for Romania. Poland fell within five weeks, with its last large operational units surrendering on October 5 after the Battle of Kock, as the Polish September Campaign ended, Hitler offered to Britain and France peace on the basis of recognition of German European continental dominance. On October 12, the United Kingdom formally refused, despite the quick campaign in the east, along the Franco-German frontier the war settled into a quiet period. This relatively non-confrontational and mostly non-fighting period between the major powers lasted until May 10,1940, and was known as the Phoney War, several other countries, however, were drawn into the conflict at this time. By September 28,1939, the three Baltic Republics felt they had no choice but to permit Soviet bases and troops on their territory, the Baltic Republics were occupied by the Soviet army in June 1940, and finally annexed to the Soviet Union in August 1940. The Soviet Union wanted to annex Finland and offered an agreement, but Finland rejected it. In the Moscow Peace Treaty of March 12,1940, Finland ceded 10% of her territory, the Finns were embittered over having lost more land in the peace than on the battlefields, and over the perceived lack of world sympathy. Meanwhile, in western Scandinavia, Germany invaded Denmark and Norway in April 1940, sweden was able to remain neutral. Most Allied forces were in Flanders, anticipating a re-run of the World War I Schlieffen Plan, as a result of this, and also the superior German communications and tactics, the Battle of France was shorter than virtually all pre-war Allied thought could have conceived. It lasted six weeks, including the Luftwaffe bombing of Paris June 3, on June 10 Italy declared war on both France and the United Kingdom, but did not gain any significant success in this campaign. French government fled Paris, and soon, France surrendered on June 22, many French soldiers, as well as those of other occupied countries, escaped to Britain. The General de Gaulle proclaimed himself the leader of Free France. Following the unexpected victory, Hitler promoted 12 generals to the rank of field marshal during the 1940 Field Marshal Ceremony. Later, on April 24,1941, the USSR gave full recognition to the Vichy government situated in the non-occupied zone in France

12.
Berlin
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Berlin is the capital and the largest city of Germany as well as one of its constituent 16 states. With a population of approximately 3.5 million, Berlin is the second most populous city proper, due to its location in the European Plain, Berlin is influenced by a temperate seasonal climate. Around one-third of the area is composed of forests, parks, gardens, rivers. Berlin in the 1920s was the third largest municipality in the world, following German reunification in 1990, Berlin once again became the capital of all-Germany. Berlin is a city of culture, politics, media. Its economy is based on high-tech firms and the sector, encompassing a diverse range of creative industries, research facilities, media corporations. Berlin serves as a hub for air and rail traffic and has a highly complex public transportation network. The metropolis is a popular tourist destination, significant industries also include IT, pharmaceuticals, biomedical engineering, clean tech, biotechnology, construction and electronics. Modern Berlin is home to world renowned universities, orchestras, museums and its urban setting has made it a sought-after location for international film productions. The city is known for its festivals, diverse architecture, nightlife, contemporary arts. Since 2000 Berlin has seen the emergence of a cosmopolitan entrepreneurial scene, the name Berlin has its roots in the language of West Slavic inhabitants of the area of todays Berlin, and may be related to the Old Polabian stem berl-/birl-. All German place names ending on -ow, -itz and -in, since the Ber- at the beginning sounds like the German word Bär, a bear appears in the coat of arms of the city. It is therefore a canting arm, the first written records of towns in the area of present-day Berlin date from the late 12th century. Spandau is first mentioned in 1197 and Köpenick in 1209, although these areas did not join Berlin until 1920, the central part of Berlin can be traced back to two towns. Cölln on the Fischerinsel is first mentioned in a 1237 document,1237 is considered the founding date of the city. The two towns over time formed close economic and social ties, and profited from the right on the two important trade routes Via Imperii and from Bruges to Novgorod. In 1307, they formed an alliance with a common external policy, in 1415 Frederick I became the elector of the Margraviate of Brandenburg, which he ruled until 1440. In 1443 Frederick II Irontooth started the construction of a new palace in the twin city Berlin-Cölln